PHP Complete Form Validation

We can create and use forms in PHP. To get form data, we have to use PHP superglobals $_GET and $_POST.

PHP Form Validation With Example

In this unit, we see a complete PHP Form with validations.

Form validation is one of the major aspects of web development in PHP. There are many vulnerabilities and threats that can put a user’s sensitive information at risk. Therefore, it is important to validate a PHP form before submitting it.

Must Read: PHP Form Email Validation

Simple PHP Registration Form Validation

Here, we will create a simple general-purpose registration form in PHP and MySQL with essential validations.

Example

<!DOCTYPE html>		

<html>		

<head>		

<style>		

.error {color: #FF0001;}		

</style>		

</head>		

<body>	

<?php		

// define variables to empty values		

$nameErr = $emailErr = $mobilenoErr = $genderErr = $websiteErr = $hobbyErr = "";		

$name = $email = $mobileno = $gender = $website = $hobby = "";		

//Input fields validation		

if ($_SERVER["REQUEST_METHOD"] == "POST") 
{		
   //String Validation		
   if (empty($_POST["name"]))
   {		
      $nameErr = "Name is required";		
   } 
   else 
   {		
      $name = input_data($_POST["name"]);		
      // check if name only contains letters and whitespace		
      if (!preg_match("/^[a-zA-Z ]*$/",$name)) 
      { 
	    $nameErr = "Only alphabets and white space are allowed";		
      }		
    }		
   //Email Validation	 	
   if (empty($_POST["email"])) 
   {		
      $emailErr = "Email is required";		
   } 
   else 
   {
	   $email = input_data($_POST["email"]);		
           // check that the e-mail address is well-formed		
           if (!filter_var($email, FILTER_VALIDATE_EMAIL)) 
           { 
	        $emailErr = "Invalid email format";		
	    }	

   }		

   //Number Validation		
   if (empty($_POST["mobileno"])) 
   {
	   	$mobilenoErr = "Mobile no is required";		
   } 
   else 
   {
	    $mobileno = input_data($_POST["mobileno"]);	
            // check if mobile no is well-formed		
	    if (!preg_match ("/^[0-9]*$/", $mobileno) ) 
            { 
	        $mobilenoErr = "Only numeric value is allowed.";		
	    }	

	    //check mobile no length should not be less and greator than 10		
            if (strlen ($mobileno) != 10) 
            {		
                $mobilenoErr = "Mobile no must contain 10 digits.";		
            }
	}		
      
        //URL Validation	 	 		
        if (empty($_POST["website"]))
        {
            $website = "";		
        }
        else
        {		
           $website = input_data($_POST["website"]);	
           // check if URL address syntax is valid		
           if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)){
           $websiteErr = "Invalid URL";
        }
        }

	//Empty Field Validation		
        if (empty ($_POST["gender"]))
        {
           $genderErr = "Gender is required";

        }
        else
        {
           $gender = input_data($_POST["gender"]);		
        }
        //Checkbox Validation		
        if (!isset($_POST['hobbies']))
        {		
          $hobbyErr = "You must select hobby.";		
        }
        else
        {
          $hobby = input_data($_POST["hobbies"]);	
        }		

}		

function input_data($data){

	$data = trim($data);		

	$data = stripslashes($data);		

	$data = htmlspecialchars($data);		

	return $data;

}		

?>		

<h2>Registration Form</h2>		

<span class = "error">* required field </span>		

<br><br>		

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" >	 		

	Name:		

	<input type="text" name="name">		

	<span class="error">* <?php echo $nameErr; ?> </span>	

	<br><br>		

	E-mail:

	<input type="text" name="email">		

	<span class="error">* <?php echo $emailErr; ?> </span>	

	<br><br>		

	Mobile No:		

	<input type="text" name="mobileno">		

	<span class="error">* <?php echo $mobilenoErr; ?> </span>	

	<br><br>		

	Website:		

	<input type="text" name="website">		

	<span class="error"><?php echo $websiteErr; ?> </span>		

	<br><br>		

	Gender:	

	<input type="radio" name="gender" value="male"> Male		

	<input type="radio" name="gender" value="female"> Female		

	<input type="radio" name="gender" value="other"> Other		

	<span class="error">* <?php echo $genderErr; ?> </span>	

	<br><br>		

	Hobbies:	

	<input type="checkbox" name="hobbies" value="Reading"> Reading	

	<input type="checkbox" name="hobbies" value="Writing"> Writing	

	<input type="checkbox" name="hobbies" value="Playing"> Playing	

	<span class="error">* <?php echo $hobbyErr; ?> </span>	

	<br><br>

	<input type="submit" name="submit" value="Submit">

	<br><br>	 	 	 	 	 	 	 	 	 	 	 	 	 	 	

</form>		

<?php		

	if(isset($_POST['submit']))	{

		if($nameErr == "" && $emailErr == "" && $mobilenoErr == "" && $genderErr == "" && $websiteErr == "" && $hobbyErr == ""){

			echo "<h3 color = #FF0001> <b>You have sucessfully registered.</b> </h3>";		

			echo "<h2>Your Input:</h2>";		

			echo "Name: " .$name;		

			echo "<br>";		

			echo "Email: " .$email;		

			echo "<br>";		

			echo "Mobile No: " .$mobileno;		

			echo "<br>";		

			echo "Website: " .$website;		

			echo "<br>";		

			echo "Gender: " .$gender;		

			echo "<br>";	

			echo "Hobby: " .$hobby;
		       } 
                       else 
                       {		
                        echo "<h3> <b>You didn't filled up the form correctly.</b> </h3>";		

		}

	}		

?>		

</body>		

</html>

Output

Registration form before submission

Complete Registration form in PHPRegistration form after submission

Complete Registration Form output in php

Conclusion

In this article, we have implemented all the steps of validating a PHP form.Β  We learnt how to apply the different validation on input fields using PHP. We hope you have gained a complete understanding of how a PHP form works.Β 

If you want to understand the other concepts of PHP programming, do refer to our PHP Tutorial and PHP MySQL sections. Happy Learning πŸ™‚

 

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